The scribing of horizontal and vertical lines relative to the orientation of the drafting work or drawing are the two most common operations in the practice of drafting. Horizontal lines are generally produced with the aid of a T-square or horizontal bar, and vertical lines are generally produced with the aid of a right triangle in conjunction with a T-square or horizontal bar. These triangles are generally used to produce a line at the commonly needed angles of 30 degrees, 45 degrees, or 60 degrees from the horizontal, and are most commonly available in 30-60 degree and 45 degree models. Despite their almost universal use, such triangles are subject to several disadvantages and problems, especially when used for the production of vertical lines. The majority of these problems stem from the fact that these triangles must be constantly flipped from one face to another face to produce the commonly needed angles. The draftsperson must constantly reposition and reverse the standard drafting triangles in order to scribe complimentary or reverse angles. This problem is especially true of the 30-60-90 degree triangle and having to flip it from face to face reducing the efficiency of the draftsperson. As a result of this need to flip the triangles from one face to another face came the need to develop a handle or method of gripping the triangle from flat drawing surfaces. This necessity often created strained working conditions and reduced the efficiency of the draftsperson. In addition, the full contact between the face of the triangle and the drawing surface often produces smearing of both graphite or ink lines on the drawing as the triangle is slid over those lines, so it is necessary for the draftsperson to position the triangle so that it is not placed directly over the last and most recently drawn lines.
There have been various approaches to try and solve these problems and they are known in the prior art, but all of these attempted solutions fall short of a combined solution addressing the real problem; the problem of efficient maneuvering and of needing to flip the triangle from one face to another face. Some beginning attempts would include L-shaped drafting instruments as illustrated by British Patent No. 386,883 and French Patent No. 730,763. They are known in the art and do alleviate some of the problems associated with the standard drafting triangle. Those instruments are, however, directed at producing an instrument capable of creating certain specific angles. Similarly, various triangle designs have been proposed, such as those illustrated by U.S. Pat. Nos. 482,023, and 4,545,130, for primarily providing an instrument capable of creating multiple angles and curves. U.S. Pat. No. 827,989 attempted to alleviate some of the problems for efficient maneuvering and no flipping of the instrument, but fell short of the combined solution because the instrument and handle did not perform in an efficient manner due to the fact that the handle location was not efficient for pivoting the instrument, hence not efficient for control. But all of the above mentioned patents still lack in solving the basic problem of efficiently maneuvering and of needing to flip the triangle from face to face.
Some solutions to try and alleviate the need of having to flip the triangle from one face to another face would include U.S. Pat. Nos. 3,555,657, and 3,375,589, which both provides a method of manufacturing a triangle with an edge for grasping with fingers, while yet another solution as illustrated by U.S. Pat. No. 4,443,953 provides a handle that can be attached to either face of the triangle, but these designs lack in efficiency still another attempted solution is illustrated by U.S. Pat. No. 4,999,922, which provides a handle for convenience but has an unnecessarily complicated shape and is not for use in pivoting and controlling instrument. Still another attempted solution is illustrated by U.S. Pat. No. 4,821,424, which provides a handle that slides through the triangle to be grasped from face to face. These designs are useful in providing a means of more readily grasping the drafting instrument with which they are used, and are meant to alleviate problems associated with flipping the instrument from face to face but again do not address the initial problem of needing to flip the instrument from face to face which results in the draftsperson being less efficient. French patent No. 1,385,756, shows the use of raised points on the face of a T-square or triangle to raise the instrument above the surface of the drafting work, which alleviates certain normal disadvantages of the use of a triangular instrument, but the design stops short of a coordinated solution to the full scope of problems associated with a triangular instrument.
It is an object of the present invention to provide a fully coordinated approach to the solution of the problems associated with the use of a standard drafting triangle without negating the advantageous features of a triangular drafting instrument by providing an initial solution that would free the standard triangular drafting instrument of superfluous features. Further, it is also the object of the present invention to provide a triangular drafting instrument with a combination of necessary features directed to performing a drafting work in a highly efficient manner.